Dimensioning A PTC Systems Using Parabola Properties

Abstract

Out of many geometric curves, parabola stands out in usage in concentrated solar power (CSP). Its reflective properties allow reflecting light into one single point. This paper gives insight into the geometry of parabolic trough concentrators from the point of designing a size of a collector regarding two inputs. The first input is a parameter of the parabola which, provides the shape and size of the reflecting surface. A second input is a deviation of the angle of incoming light. Usually, this angle is perpendicular to the parabola's directrix, but the sizing of the collector tube must consider that because manufacturing or any other inaccuracy reflected ray might disperse from the focal point of the parabola. A detailed view of this dissipation of reflected rays depending on the entering ray's angle will be explained in the paper. A geometrical and algebraic display will be given, and a formula for sizing collector will be derived. In this equation two input values will be combined: parameter of parabola and value of the deviation of entering ray of light. This gained formula can later be used to show dependence between these two inputs and provide the answer to a question: is there a way to construct a mechanism that will move the focal point in accordance to changing entering angle and parameter of a parabola?